Oral squamous cell carcinoma (OSCC) claims the lives of thousands in the U.S. and hundreds of thousands worldwide annually. A biopsy followed by histopathology, the gold standard for the diagnosis of OSCC, is painful, invasive, costly, not practical if longitudinal assessments of the same lesion are required and oftentimes is not available or imprecise in third world countries. A tool that quickly distinguishes cancerous from non- cancerous lesions and identifies progressive or transforming lesions could allow for early intervention, which would improve outcomes and negate the need for unnecessary biopsies in patients whose lesions remain benign or haven?t begun to degenerate. Therefore, there is an unmet need for a rapid, non-invasive, objective and cost-effective test for OSCC. We and others have reported that an altered expression profile of human beta defensin 3 (hBD-3), an epithelial cell derived antimicrobial peptide (AMP), and hBD-2, another epithelial cell AMP, is an early event in OSCC. Therefore, the ratio of hBD-3 and hBD-2 in the lesion, when compared to the contralateral site, could be exploited in distinguishing OSCC from other lesions of the oral cavity. We refer to this ratio as the beta defensin index (BDI). Our ongoing clinical study of 78 subjects with suspicious oral lesions demonstrated high sensitivity (100%) and specificity (74%) of the ELISA based BDI in distinguishing cancerous from noncancerous oral lesions (P<0.0001). With the high accuracy (98%) of our BDI based molecular assay, we now wish to advance our novel platform from the laborious, time consuming ELISA format into an imaging-based point-of-care (POC) device that utilizes microfluidic technology to quantify the BDI with an expected turnover time of half an hour. Our microfluidic intact cell assay (MICA) approach to developing a POC device for oral cancer detection is unique; it utilizes intact epithelial cells trapped in a microfluidic chip encompassing microfabricated pillar arrays with varying spaces to allow the capture of epithelial cells. Upon capture, the cells are permeabilized and labeled with fluorescent antibodies for hBD ratio analysis. We employ automated fluorescence imaging and computational algorithm to enable automated calculation of the BDI scores. We now hypothesize that the ELISA format that can effectively detect oral cancer, can be configured for point of care MICA, retaining its high accuracy and making it easier to use worldwide. To advance the discovery of this new approach for oral cancer detection, we propose the following aims: 1. Develop a working prototype of a MICA POC device for oral cancer testing equipped with cell imaging and BDI calculation capabilities. 2. Conduct a discovery phase study where MICA POC and ELISA, as independent assays, will be compared with pathology review in their ability to detect oral cancer. The MICA POC, while not intending to replace biopsy, could be deployed, in the future, to objectively and non- invasively determine who actually needs a biopsy, monitor oral premalignant lesions in real world practice and fulfill a major unmet need in low-socio economic countries where pathology review is lacking and/or unreliable.